Browsing by Author "WU, HH"

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A NEW RESCHEDULING METHOD FOR COMPUTER-BASED SCHEDULING SYSTEMS
(1995-08-01)
WU, HH
;
LI, RK
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Providing a powerful interactive tool for the scheduler to quickly and easily react to the inevitable rescheduling changes is mandatory in today's complex and flexible manufacturing environment. The conventional approaches either employ the regeneration method, which results in unsatisfactory response times, or use methods that require too much manual intervention for editing operations to be changed. A new rescheduling method is proposed in this paper which addresses these problems. The fundamental scheme of this rescheduling method is based on a scheduling graph as well as concepts of time effect and relationship effect. The scheduling graph is an alternative representation structure of a schedule Gantt chart. The time effect and relationship effect provide functions of (1) identifying those operations that require revision, (2) revising those identified affected operations (via a partial change of the scheduling graph structure) and (3) updating starting and ending times of those revised operations. The rescheduling method both reduces manual intervention of rescheduling to a minimum and permits net change (opposite to regeneration) rescheduling to be achievable. This rescheduling method can be embedded in current computer assistance scheduling systems so as to enhance their effectiveness.
ELECTROOPTIC PHASE TRACKING OF MICROWAVE SIGNALS BEYOND 18.5 GHZ USING AN INTEGRATED ELECTROOPTIC MODULATOR AS AN OPTOELECTRONIC HARMONIC MIXER IN A PHASE-LOCK LOOP
(1994-04-01)
PAN, CL
;
LIN, GR
;
CHYOU, DY
;
WU, HH
;
交大名義發表
We demonstrate electrooptic phase tracking of microwave signals beyond 18.5 GHz using a gain-switched laser diode as the optical clock. The key element of this system is a fiber-pigtailed integrated-optic Mach-Zehnder Modulator (IOM). The IOM functions as an optoelectronic harmonic mixer in a phase lock loop. The conversion loss of the OEHM is 66dB. The phase error and the single sideband phase noise density of the phase- locked 18.5 GHz signal is 5.6 x 10(-5) rad/square-root Hzand -54 dBc/Hz, respectively.
ELECTROOPTIC SAMPLING OF OPTOELECTRONICALLY PHASE-LOCKED 10.0 GHZ MICROWAVE SIGNALS USING SEMICONDUCTOR-LASER DIODES
(1991-08-29)
WU, HH
;
CHANG, CS
;
PAN, CL
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光電工程學系
;
電信研究中心
10.0 GHz microwave signals optoelectronically phase locked by a laser-diode-based GaAs: Cr photoconductive harmonic mixer (lambda = 0.81-mu-m) have been measured noninvasively using the electro-optic sampling technique with a pin-switched InGaAsP laser diode (lambda = 1.3-mu-m).
FEATURE MODIFICATION FRAMEWORK FOR FEATURE-BASED DESIGN SYSTEMS
(1995-02-01)
LI, RK
;
LIN, CY
;
WU, HH
;
交大名義發表
;
工業工程與管理學系
Design features created by a feature based design system could theoretically be directly sent to machining preparation system. This, however, has not been found and feature modification is still necessary. A feature modification framework is proposed in this paper for bridging the gap between the design features and machining features. Feature modification algorithms were also developed for the foundation of the framework. A prototype system is presented and illustrated by an explanation of how the feature modification concept could function in a real situation.
NEAR-INFRARED TRANSMISSION MEASUREMENT OF EL2 CONCENTRATION IN SEMIINSULATING GAAS WAFERS WITH A LASER DIODE (LAMBDA=1.3-MU-M)
(1991-07-01)
PAN, CL
;
WU, HH
;
HSIEH, TR
;
交大名義發表
;
光電工程學系
We demonstrated a near-infrared transmittance setup for EL2 concentration mapping in undoped semi-insulating (SI) GaAs wafers. The light source was a power-stabilized laser diode (lambda = 1.3-mu-m) operating in the light emitting diode (LED) mode. The sensitivity of the apparatus was as low as 10(14) cm-3 for typical commerical wafers 350-mu-m in thickness.
OPTOELECTRONIC PHASE TRACKING AND ELECTROOPTIC SAMPLING OF FREE-RUNNING MICROWAVE SIGNALS UP TO 20 GHZ IN A LASER-DIODE-BASED SYSTEM
(1995-06-01)
WU, HH
;
LIN, GR
;
PAN, CL
;
光電工程學系
;
Department of Photonics
We report optoelectronic phase-tracking and electrooptic sampling of microwave signals from a free-running oscillator in a laser-diode-based system. A voltage-controlled oscillator (VCO) in a photoconductive harmonic mixer based phase-lock loop is utilized to gain switch a 0.8 mu m laser diode for phase-tracking of the microwave signal at frequencies up to 20 GHz. Phase and amplitude of the microwave signal in a microstrip Line is also measured using another 1,3-mu m laser diode driven by the VCO.
OPTOELECTRONIC PHASE-LOCKING OF MICROWAVE SIGNALS UP TO 4GHZ USING A LASER-DIODE-BASED ELECTROOPTIC HARMONIC MIXER
(1993-01-01)
PAN, CL
;
TANG, KY
;
WU, HH
;
光電工程學系
;
Department of Photonics
OPTOELECTRONIC PHASE-TRACKING AND WAVE-FORM DISPLAY OF MICROWAVE SIGNALS UP TO 8 GHZ USING GAIN-SWITCHED LASER-DIODES
(1994-05-15)
WU, HH
;
WANG, CL
;
LIN, GR
;
CHANG, CS
;
PAN, CL
We present a new, more versatile scheme for maintaining phase coherence between optical probe pulses and microwave signals under test in a laser-diode-based optoelectronic sampling system. This approach takes advantage of the relative ease of changing the repetition rate of the gain-switched laser diode (GSLD). The microwave signal to be sampled is used as the clock signal for phase-locking of a voltage controlled-oscillator (VCO) which drives the GSLD. Phase-tracking and display of waveforms at frequencies up to 8 GHz have been realized. It is also shown that lower phase noise sidebands for the phase-locked VCO can be realized by locking the higher harmonics of the laser pulse to the microwave clock.
OPTOELECTRONIC SYNCHRONIZATION OF DISTRIBUTED MICROWAVE-OSCILLATORS USING SEMICONDUCTOR-LASER DIODES
(1992-09-01)
WU, HH
;
CHANG, CS
;
PAN, CL
;
交大名義發表
;
光電工程學系
We report a laser-diode-based system for optoelectronic synchronization of two distributed microwave oscillators at 10-GHz. The relative phase between the 10-GHz signals can be continuously tuned over a complete cycle by an optical delay line. Phase-locking of the two oscillators with a frequency offset of 10 kHz is also demonstrated. This method can be used to synchronize millimeter-wave oscillators for distributed architectures via fiber-optic links in the future.
SYNCHRONIZATION OF ELECTRICAL AND OPTICAL SIGNALS BY USING AN OPTOELECTRONIC TIMING DISCRIMINATOR IN A PHASE-LOCK LOOP
(1992-11-01)
PAN, CL
;
WU, HH
;
交大名義發表
;
光電工程學系
;
National Chiao Tung University
A GaAs:Cr photoconductive switch is employed as an optoelectronic timing discriminator or phase detector in the phase-lock loop. Timing information is derived from the temporally sloped output of the switch, which is the cross-correlation function of the electrical signal and the photoconductive response induced by the laser pulse train. Optoelectronic synchronization of microwave signals up to 12 GHz in a laser-diode-based system has been demonstrated. The long-term relative timing jitter between the electrical and optical signals is estimated from the error signal in the PLL to be less than 500 fs. This technique can also be used to synchronize lasers.